# How to calculate Signal Power using ADC samples?

1. ## How to calculate Signal Power using ADC samples?  Reply With Quote

•

2. ## Re: How to calculate Signal Power using ADC samples?

Hi,

An ADC just converts an analog signal into a digital signal.
You need to read the datasheet about the data format.

To get the spectrum you need:
* a known, fixed, stable sampling rate
* take 2^n samples (where n should be in integer to perform an FFT. E.g. n= 10 for 1024 samples)
* use a windowing function
* perform the FFT
* calculate the absolute (vector length) of the each output bin (real and imag part)
* do the logarithmic calculation for each output value
* do the X-Y plot

For 2^n samples you get 2^(n-1) frequency results.
The frequency step size is linear and is f_sample / 2^(n), starting with 0Hz = DC.

******
For more detailed informations you need to read basic informations first. (A forum can not replace this).
******
There will be software tools that help you do all the (mathematical) functions for you.
******
The power can be calculated by performing an RMS calculation over the desired count of samples.

Klaus  Reply With Quote

•

3. ## Re: How to calculate Signal Power using ADC samples?

http://www.sjsu.edu/people/burford.f...utorial_NI.pdf

NI has some good info: "According to the Nyquist criterion, the sampling frequency, Fs, must be at least twice the maximum frequency component in the signal. If this criterion is violated, a phenomenon known as aliasing occurs"
Sean  Reply With Quote

--[[ ]]--